I re-ran the test with my N800/OS2007/330MHz/Opera setup: The speed seems to depend on how many bricks there are left. It starts out at an average of 30 (as reported before), then it steadily increases until there are no bricks left. At that point it hovers between 39 and 41.

On my desktop the number of bricks don't matter, it's steady at 95 all the time. But then again it doesn't use any CPU either. Presumably it's all limited by the graphics card there.